1. Field of the Invention
This invention relates to a process for pulverization and separation and a process for pulverization, separation and size-regulation as well as an apparatus for pulverization and separation, an apparatus for pulverization and granulation or pulverization, separation and granulation and an apparatus for polishing and size-regulation.
More specifically, the present invention is applicable to:
A pulverizing and separating process in which a variety of molded resin articles covered on their surfaces with resin films composed mainly of a resin material for decorating and/or protecting purposes are crushed into a plurality of a coarse particle-form of small pieces and the resin films are separated and removed from the small pieces to regenerate them as a raw-form of resin material;
A pulverizing, separating and size-regulating process wherein the resin material mentioned above is regulated to a suitable particle size, if required, to regenerate it in the form of a resin material comprising particles lying in a given particle diameter range, so that second-mentioned resin material can be recycled;
A pulverizing and separating process wherein a conductive material such as copper or aluminum is separated by pulverization from a covering material that is used with insulating electrical wires or cords, for instance, vinyl chloride, crosslinked polyethylene or synthetic rubber;
A separating process wherein plastics that are insulators for various components such as computer or word processor components are separated from metals that are conductors inclusive of semiconductors or a process for separating insulators from conductors;
A pulverizing and separating apparatus which can be used to treat resin materials;
An apparatus for separating and removing the resin films from the coarse particle-form of small pieces, or for crushing molded powder articles including a relatively hard, molded resin article (that may also hereinafter be referred to simply as the powder articles) to obtain a plurality of a coarse particle-form of materials including a relatively hard resin material (that may also hereinafter be referred to simply as the powder materials) and pulverizing or frictionally crushing the powder materials within a given particle diameter range or to a given thickness; and
A pulverizing and granulating or pulverizing, separating and granulating apparatus and a polishing and size-regulating apparatus wherein molded powder articles including a relatively soft, molded resin article (that may also hereinafter be referred to simply as the molded powder articles) are crushed to obtain a coarse particle-form of powder materials including a relatively soft resin material and the powder materials can then be regulated in terms of size and granulated.
2. Description of the Prior Art
Generally, resin articles shaped and formed of resin materials such as a variety of naturally occurring or synthetic resins are now used in many applications, both in many types and in large amounts, incidental to a variety of life styles. At present, however, such various problems as mentioned below arise in connection with their post-use treatments.
As well known in the art, most resin materials constituting molded resin articles are characterized by their own properties, i.e. they have excellent water resistance and weather resistance and are difficult to corrode, but they spew about large amounts of harmful gases and fumes that are undesired in view of society and environment, for instance, when incinerated in an incinerator for disposal purposes. In addition, there is a disadvantage that uncombusted components of the resin material melt during incineration and are deposited onto the inner wall of the incinerator, presenting a risk of doing damage to it. Warding off this defect may be achieved by burying the molded resin articles underground. However, since they remain uncorroded over an extended period, they appear to present another factor for environmental disruption.
On the other hand, such resin materials will yearly be exhausted due to resource depletion, and it is now demanded and recognized that the post-use resin materials must be recycled without disposal. For such recycling or regenerating purposes, what types of resins are used are indicated on the molded resin articles.
Usually or in most cases, molded resin articles to be recycled for the recycling purposes mentioned above are provided on their surfaces with resin films for decorating, that is to say, polishing, matting and coloring purposes or with a view to improving their properties such as wear resistance and weather resistance much more considerably or, in other words, protecting them. As an example, about 75% by weight material of a car is now recycled, but most of it is a metal material and the rest or 25% is rejected in the form of dust, in which about 30% by weight of plastics are contained. For instance, bumper parts for various vehicles are usually produced by applying a polyester urethane type coat of about 15 .mu.m to 30 .mu.m in thickness onto a substrate member made of polypropylene and having a thickness of about 2.5 mm to 5 mm.
Generally, the resin films coated on the surfaces of the molded resin articles are formed with the use of resin materials differing from those forming such articles in terms of type and properties, or alternatively formed of resin materials of different colors. When such resin materials of varying types and with varying properties and colors are recycled as such, not only are articles obtained by this recycling much inferior in terms of mechanical properties such as impact strength, but any surface smoothness and color as desired cannot be obtained as well.
Until now, the molded resin articles to be recovered have usually been recycled for each resin material having the same type and properties with the foregoing in mind.
However, the resin films coated on the surfaces of molded resin articles are so relatively thin and have such strong adhesion strength that they cannot easily peel off; that is, they are likely to have various undesired properties and so are not well suited for mechanical treatments; thus throughputs are low even when relying upon mechanical peeling and discriminating means such as well-known shot blasting. Another disadvantage is that when it is intended to peel and discriminate off such resin films by pulverizer means such as ball-milling, they cannot easily peel off, because they melt by frictional heat during pulverization.
For instance, when it is intended to feed the materials to be treated into a specific treating zone through a feeding opening such as a hopper, the materials build up even in the hopper and so agglomerate to provide a solid matter that is not fed into the hopper in a stable manner. To add to this, there may be another disadvantage that clogging or other trouble is likely to occur among the individual materials to be treated in the treating zone.
In order to subject the resin materials differing in type and properties to a separation-by-dissolution treatment with the use of an organic solvent that allows them to be associated with each other, it is required that the polypropylene material itself be denatured, and the need of using a melting-by-heating step or other additional steps lowers throughputs. This in turn causes treating equipment to be excessively increased in size, offering an economical problem and, besides, poses much difficulty due to the need of post-treatments such as the step of neutralizing the used solvent.
The problems associated with the recovery of the resin materials mentioned above, for the most part, are true of other powder materials as well.
In some cases, resin films must be released and removed from such articles of resin material as mentioned above, for example, resin materials deposited with said resin films on them or powder materials containing resin materials alone. When the material to be treated is so relatively hard that it must be pulverized within a given particle diameter range, or when it is relatively soft, it is often required to be granulated with the particle diameters lying within a given range. In addition, these operations should be carried out by a single treating apparatus. However, there is still no treating arrangement meeting and accommodating such demands, although this is partly because of such considerations as mentioned above.
Further, when it is intended to recycle copper, aluminum or other material that are conductors by removing a covering insulator material from insulated electrical wires or cords, the conductor portions are pulled out of the covering material while it is torn in the lengthwise direction. Alternatively, lengthwise cutouts are provided in the covering material, and the wires or cords are then cut to a given length. After that, torsion is induced in the cut wires or cords to separate the covering material from the conductors.
When the covering material is combustible, it is attempted to burn off that material completely in an incinerator as well.
Conventional means for removing covering insulator materials physically or torsionally have some defects or, in other words, they are low in separation efficiency or are impractical.
Burning off the covering material that is an insulator is easy to carry out, but poses some problem, i.e., gives rise to spewing about harmful gases or large amounts of fumes and reducing the serviceability of the furnace.
In the case of computers and word processors no longer suitable for use, a number of conductors inclusive of semiconductors and other parts incorporated in them are simply thrown away with them. As well known in the art, many metals such as semiconductors are used while molded with plastics that are conductors, and so are desired to be recovered and recycled in view of making effective use of resources. However, never until now are any effective means meeting such demand proposed.